Case study — social housing

Energy efficient electric hot water for New Forest District Council

Sixteen council properties moved from night storage heaters and old vented hot water systems to modern high heat retention heating and Sunamp heat batteries.

  • Client

    New Forest District Council

  • Scale

    16 social housing properties

  • Heating

    High heat retention storage heaters, 2–3 per property

  • Hot water

    Sunamp Thermino heat batteries

The brief

Old storage heaters, old cylinders, sixteen homes

New Forest District Council contracted us to upgrade the heating and hot water across sixteen of its social housing properties. The homes were running on night storage heaters, with hot water from old vented cylinder systems.

Social housing puts the two halves of a heating decision in different hands: the council owns the equipment, and the tenant pays the bill it produces. A night storage heater gives out its heat on its own overnight-charge schedule rather than when the household wants it, and an old vented cylinder spends part of every day keeping itself warm — so the equipment the landlord owns sets the running costs the tenant carries. Upgrading it is one of the most direct things a landlord can do about that, which is why councils keep commissioning exactly this swap.

We handled the full scope — from planning with the council through to the finished installations.

Heat battery units of several sizes displayed in a demonstration room

The scope, walked through

  1. Planning the upgrade with the council

    Sixteen homes is a programme, not a job — planned with the council before anything was unbolted.

  2. Product recommendation for each property type

    Different property types need different equipment, so each type got its own recommendation rather than one specification stretched across all sixteen.

  3. Removal of the old heaters and cylinders

    The night storage heaters and the old vented cylinders came out of every property.

  4. Disposal of everything taken out

    Old storage heaters and cylinders are heavy, awkward items — disposing of them was our job, not the council’s.

  5. Replacement, testing and handover

    The new heating and hot water installed, tested and handed over, property by property.

What we installed

Heat retention heating, heat battery hot water

Each property's night storage heaters were replaced with modern high heat retention storage heaters — two to three per property, sized to the rooms they serve. A high heat retention heater works on the same off-peak principle as the units it replaced, but with a far better insulated core and controllable output: it holds on to its overnight charge instead of leaking it into the room all morning, and releases it when the heating is actually wanted.

The old vented hot water systems came out in favour of Sunamp heat batteries. A heat battery stores heat in a phase-change material rather than a tank of standing water, which makes it dramatically more compact than the cylinder it replaces. Per Sunamp's published article on the project, one-bedroom flats received the Thermino ePlus 70 and two-bedroom flats the ePlus 150 — each property type getting its own specification.

We are approved Sunamp installers
Side-by-side comparison of a bulky hot water cylinder and a compact heat battery in a cupboard

As reported by Sunamp

What the manufacturer wrote about this project

Sunamp published its own account of the New Forest District Council upgrade. In it, Sunamp reports that installs took around half a day per flat, that the heat batteries deliver hot water at mains pressure, and that they charge on off-peak electricity.

Sunamp also describes what the upgrade replaced day-to-day:

Residents had been switching their old cylinders off to save money and boiling kettles for hot water instead.

That detail is the whole project in one line. A hot water system that people turn off to save money isn't really providing hot water — and it is the situation this kind of upgrade exists to address.

More case studies

Upgrading social housing or rental stock?

We plan, remove, dispose and replace — heating and hot water, at scale or one property at a time.